It has heretofore been known that cycloolefin random copolymers obtained by copolymerization of ethylene and cycloolefins, such as tetracyclododecene, are synthetic resins which are excellent in transparency, and also well balanced among heat resistance, thermal aging resistance, chemical resistance, solvent resistance, dielectric characteristics and rigidity. Such cycloolefin random copolymers as mentioned above are known to exhibit excellent performance in the field of optical materials such as optical memory disc and optical fiber. (See, for example, Japanese Patent L-O-P Publns. Nos. 168708/1985, 98780/1986, 115912/1986, 115916/1986, 120816/1986 and 252407/1987).
The cycloolefin random copolymers referred to hereinabove are synthetic resins which are particularly excellent in heat resistance, rigidity and transparency, however, their impact resistance is not always sufficient, and hence a further improvement in their impact resistance is required.
By the way, the present applicant has proposed by way of Japanese Patent L-O-P Publn. No. 255145/1991 resin compositions comprising a cycloolefin random copolymer obtained by copolymerization of ethylene and cycloolefins, such as tetracyclododecene, and an elastomeric polymer (rubber). However, the impact resistance of this resin composition is not always sufficient for the requirements as intended, though the resin composition is improved in impact resistance in comparison with the cycloolefin random copolymer prior to blending with the elastomeric polymer.
The reason why the resin composition obtained generally by melt blending the cycloolefin random copolymer and elastomeric polymer by means of a Brabender Plasti-Corder or an extruder has not sufficiently been improved in impact resistance is considered ascribable to the fact that the compatibility of the cycloolefin random copolymer with the elastomeric polymer is not always favorable.
With the view of solving such problem associated with the prior art as mentioned above, the present inventors prosecuted extensive researches on this subject, whereby they have found that
(1) a cycloolefin copolymer composition obtained by copolymerization of an .alpha.-olefin having at least 2 carbon atoms, such as ethylene, and a cycloolefin in the presence of a hydrocarbon elastomer substantially free from a polymerizable double bond, said composition containing a specific amount of the above-mentioned hydrocarbon elastomer substantially free from the polymerizable double bond, and PA1 (2) a cycloolefin copolymer composition obtained by copolymerization of an .alpha.-olefin having at least 2 carbon atoms, such as ethylene, and a cycloolefin in the presence of a hydrocarbon elastomer having a polymerizable carbon-carbon double bond, said composition containing a specific amount of the above-mentioned hydrocarbon elastomer having the polymerizable carbon-carbon double bond, have excellent impact resistance, and eventually they have accomplished the present invention. PA1 [A] a hydrocarbon elastomer (A-1) component substantially free from a polymerizable double bond, and having an intrinsic viscosity [.eta.], as measured in decalin at 135.degree. C., of from 0.05 to 10 dl/g and a glass transition temperature (Tg) of less than 10.degree. C., and PA1 [B] a cycloolefin random copolymer (B-1) component obtained by copolymerization of (a) an .alpha.-olefin of at least 2 carbon atoms and (b) a cycloolefin represented by the following formula [I] or [II] in the presence of the abovementioned hydrocarbon elastomer (A-1) component, said composition containing the above-mentioned hydrocarbon elastomer (A-1) component in an amount of 1-50% by weight. ##STR1## wherein n is 0 or 1; m is 0 or a positive integer; q is 0 or 1; R.sup.1 -R.sup.18, R.sup.a and R.sup.b are each independently a hydrogen atom, a halogen atom or a hydrocarbon group; R.sup.15 -R.sup.18 may be linked with one another to form a monocyclic or polycyclic group which may have a double bond; and R.sup.15 and R.sup.16, or R.sup.17 and R.sup.18 may together form an alkylidene group; ##STR2## wherein each p and q is independently 0 or an integer of 1 or more; each of m and n is independently 0, 1 or 2; R.sup.1 -R.sup.19 are each independently a hydrogen atom, a halogen atom, an aliphatic hydrocarbon group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group or an alkoxy group; a carbon atom to which R.sup.9 (or R.sup.10) is linked and a carbon atom to which R.sup.13 or R.sup.11 is linked may be bonded directly or by way of an alkylene group of 1-3 carbon atoms, and R.sup.15 and R.sup.12 or R.sup.15 and R.sup.19 may be linked together to form a monocyclic or polycyclic aromatic ring when each of n and m is 0. PA1 (a) an .alpha.-olefin of at least 2 carbon atoms and PA1 (b) a cycloolefin represented by the aforementioned formula [I] or [II] in a liquid phase in the presence of a hydrocarbon elastomer substantially free from a polymerizable double bond and having an intrinsic viscosity [.eta.], as measured in decalin at 135.degree. C., of 0.05-10 dl/g and a glass transition temperature (Tg) of less than 10.degree. C. to obtain a composition containing the above-mentioned hydrocarbon elastomer (A-1) component in an amount of 1-50% by weight. PA1 [A] a hydrocarbon elastomer (A-2) component having an intrinsic viscosity [.eta.], as measured in decalin at 135.degree. C., of 0.05-10 dl/g, a glass transition temperature (Tg) of less than 10.degree. C., a polymerizable double bond, and an iodine value of 2-30 (g-iodine/100 g-polymer), and PA1 [B] a cycloolefin random copolymer (B-2) component obtained by copolymerizing PA1 (i) an .alpha.-olefin of at least 2 carbon atoms, PA1 (ii) a cycloolefin represented by the aforesaid formula [I] or [II] and PA1 (iii) a non-conjugated diene having 5-20 carbon atoms, and containing a structural unit derived from the abovementioned cycloolefin in an amount of at least 3 mol % and having an intrinsic viscosity [.eta.], as measured in decalin at 135.degree. C., of 0.5-5.0 dl/g, a glass transition temperature (Tg) of less than 10.degree. C., a polymerizable carbon-carbon double bond and an iodine value of 2-30 (g-iodine/100 g-polymer), said composition containing the above-mentioned cycloolefin elastomer (A-3) component in an amount of 8-40% by weight. PA1 (i) an .alpha.-olefin copolymer and PA1 (ii) an .alpha.-olefin/cycloolefin copolymer. PA1 ethylene/propylene copolymer, ethylene/1-butene copolymer, ethylene/1-pentene copolymer, ethylene/1-hexene copolymer, ethylene/4-methyl-l-pentene copolymer, ethylene/1-octene copolymer, ethylene/1-decene copolymer, ethylene/1-dodecene copolymer, ethylene/1-tetradecene copolymer, ethylene/1-hexadecene copolymer, ethylene/1-octadecene copolymer, ethylene/1-eicosene copolymer, PA1 propylene/1-butene copolymer, propylene/1-pentene copolymer, propylene/1-hexene copolymer, propylene/4-methyl-1-pentene copolymer, propylene/1-octene copolymer, propylene/1-decene copolymer, propylene/1-dodecene copolymer, propylene/1-tetradecene copolymer, propylene/1-hexadecene copolymer, propylene/1-octadecene copolymer and propylene/1-eicosene copolymer. PA1 ethylene/norbornene copolymer, ethylene/5-methyl-2-norbornene copolymer, ethylene/5-ethyl-2-norbornene copolymer, ethylene/5-propyl-2-norbornene copolymer, ethylene/5-butyl-2-norbornene copolymer, ethylene/5-pentyl-2-norbornene copolymer, ethylene/5-hexyl-2-norbornene copolymer, ethylene/5-heptyl-2-norbornene copolymer, ethylene/5-octyl-2-norbornene copolymer, ethylene/5-nonyl-2-norbornene copolymer, ethylene/5-decyl-2-norbornene copolymer, ethylene/5-undecyl-2-norbornene copolymer, ethylene/5-dodecyl-2-norbornene copolymer, ethylene/5-phenyl-2-norbornene copolymer, ethylene/tetracyclododecene copolymer, PA1 ethylene/propylene/norbornene copolymer, ethylene/propylene/5-ethylidene-2-norbornene copolymer, ethylene/propylene/5-methyl-2-norbornene copolymer, ethylene/propylene/5-ethyl-2-norbornene copolymer, ethylene/propylene/5-propyl-2-norbornene copolymer, ethylene/propylene/5-butyl-2-norbornene copolymer, ethylene/propylene/5-pentyl-2-norbornene copolymer, ethylene/propylene/5-hexyl-2-norbornene copolymer, ethylene/propylene/5-heptyl-2-norbornene copolymer, ethylene/propylene/5-octyl-2-norbornene copolymer, ethylene/propylene/5-nonyl-2-norbornene copolymer, ethylene/propylene/5-decyl-2-norbornene copolymer, ethylene/propylene/5-undecyl-2-norbornene copolymer, ethylene/propylene/5-dodecyl-2-norbornene copolymer, ethylene/propylene/5-phenyl-2-norbornene copolymer, ethylene/propylene/tetracyclododecene copolymer, PA1 ethylene/1-butene/norbornene copolymer, ethylene/1-butene/5-ethylidene-2-norbornene copolymer, ethylene/1-butene/5-methyl-2-norbornene copolymer, ethylene/1-butene/5-ethyl-2-norbornene copolymer, ethylene/1-butene/5-propyl-2-norbornene copolymer, ethylene/1-butene/5-butyl-2-norbornene copolymer, ethylene/1-butene/5-pentyl-2-norbornene copolymer, ethylene/1-butene/5-hexyl-2-norbornene copolymer, ethylene/1-butene/5-heptyl-2-norbornene copolymer, ethylene/1-butene/5-octyl-2-norbornene copolymer, ethylene/1-butene/5-nonyl-2-norbornene copolymer, ethylene/1-butene/5-decyl-2-norbornene copolymer, ethylene/1-butene/5-undecyl-2-norbornene copolymer, ethylene/1-butene/5-dodecyl-2-norbornene copolymer, ethylene/1-butene/5-phenyl-2-norbornene copolymer, ethylene/1-butene/tetracyclododecene copolymer, PA1 ethylene/1-hexene/norbornene copolymer, ethylene/1-hexene/5-methyl-2-norbornene copolymer, ethylene/1-hexene/5-ethyl-2-norbornene copolymer, ethylene/1-hexene/5-propyl-2-norbornene copolymer, ethylene/1-hexene/5-butyl-2-norbornene copolymer, ethylene/1-hexene/5-pentyl-2-norbornene copolymer, ethylene/1-hexene/5-hexyl-2-norbornene copolymer, ethylene/1-hexene/5-heptyl-2-norbornene copolymer, ethylene/1-hexene/5-octyl-2-norbornene copolymer, ethylene/1-hexene/5-nonyl-2-norbornene copolymer, ethylene/1-hexene/5-decyl-2-norbornene copolymer, ethylene/1-hexene/5-undecyl-2-norbornene copolymer, ethylene/1-hexene/5-dodecyl-2-norbornene copolymer, ethylene/1-hexene/5-phenyl-2-norbornene copolymer, ethylene/1-hexene/tetracyclododecene copolymer, PA1 ethylene/1-octene/norbornene copolymer, ethylene/1-octene/5-methyl-2-norbornene copolymer, ethylene/1-octene/5-ethyl-2-norbornene copolymer, ethylene/1-octene/5-propyl-2-norbornene copolymer, ethylene/1-octene/5-butyl-2-norbornene copolymer, ethylene/1-octene/5-pentyl-2-norbornene copolymer, ethylene/1-octene/5-hexyl-2-norbornene copolymer, ethylene/1-octene/5-heptyl-2-norbornene copolymer, ethylene/1-octene/5-octyl-2-norbornene copolymer, ethylene/1-octene/5-nonyl-2-norbornene copolymer, ethylene/1-octene/5-decyl-2-norbornene copolymer, ethylene/1-octene/5-undecyl-2-norbornene copolymer, ethylene/1-octene/5-dodecyl-2-norbornene copolymer, ethylene/1-octene/5-phenyl-2-norbornene copolymer, ethylene/1-octene/tetracyclododecene copolymer, PA1 ethylene/1-decene/norbornene copolymer, ethylene/1-decene/5-methyl-2-norbornene copolymer, ethylene/1-decene/5-ethyl-2-norbornene copolymer, ethylene/1-decene/5-propyl-2-norbornene copolymer, ethylene/1-decene/5-butyl-2-norbornene copolymer, ethylene/1-decene/5-pentyl-2-norbornene copolymer, ethylene/1-decene/5-hexyl-2-norbornene copolymer, ethylene/1-decene/5-heptyl-2-norbornene copolymer, ethylene/1-decene/5-octyl-2-norbornene copolymer, ethylene/1-decene/5-nonyl-2-norbornene copolymer, ethylene/1-decene/5-decyl-2-norbornene copolymer, ethylene/1-decene/5-undecyl-2-norbornene copolymer, ethylene/1-decene/5-dodecyl-2-norbornene copolymer, ethylene/1-decene/5-phenyl-2-norbornene copolymer, ethylene/1-decene/tetracyclododecene copolymer, PA1 (i) catalysts formed from a soluble vanadium compound and an organoaluminum compound (1), or PA1 (ii) catalyst formed from a metallocene compound of a transition metal selected from the IV B group of the periodic table or lanthanide series and an organoaluminum oxy compound and, if necessary, organoaluminum compound (2). PA1 VO(OR).sub.a V.sub.b or V(OR).sub.c X.sub.a PA1 VOCl.sub.3, PA1 VO(OC.sub.2 H.sub.5)Cl.sub.2, PA1 VO(OC.sub.2 H.sub.5).sub.2 Cl, PA1 VO(O--iso--C.sub.3 H.sub.7)Cl.sub.2, PA1 VO(O--n--C.sub.4 H.sub.9)Cl.sub.2, PA1 VO(OC.sub.2 H.sub.5).sub.3, VOBr.sub.2, VCl.sub.4, VOCl.sub.2, PA1 VO(O--n--C.sub.4 H.sub.9).sub.3 and PA1 VOCl.sub.3 .multidot.2(OC.sub.8 H.sub.17 OH). PA1 hydrogen containing electron donors, such as alcohols, phenols, ketones, aldehydes, carboxylic acids, organic acid halides, esters of organic or inorganic acids, ethers, diethers, acid amides, acid anhydrides, alkoxysilanes and the like, and PA1 nitrogen containing electron donors, such as ammonias, amines, nitriles, pyridines, isocyanates and the like; PA1 more concretly, PA1 alcohols having from 1 to 18 carbon atoms, such as methanol, ethanol, propanol, butanol, pentanol, hexanol, 2-ethylhexanol, octanol, dodecanol, octadecyl alcohol, oleyl alcohol, bnenzyl alcohol, phenylethyl alcohol, cumyl alcohol, isopropyl alcohol, isopropylbenzyl alcohol and the like, PA1 halogen containing alcohols having from 1 to 18 carbon atoms, such as trichloromethanol, trichloroethanol, trichlorohexanol and the like, PA1 phenols which have from 6 to 20 carbon atoms and may have a lower alkyl group, such as phenol, cresol, xylenol, ethylphenol, propylphenol, nonyl phenol, cumyl phenol, naphthol and the like, PA1 ketones having from 3 to 15 carbon atoms, such as acetone, methylethyl ketone, methylisobutyl ketone, acetophenone, benzophenone, benzoquinone and the like, PA1 aldehydes having from 2 to 15 carbon atoms, such as acetaldehyde, propionaldehyde, octylaldehyde, benzaldehyde, tolualdehyde, naphthaldehyde and the like, PA1 organic acid esters having from 2 to 18 carbon atoms, such as methyl formate, methyl acetate, ethyl acetate, vinyl acetate, propyl acetate, octyl acetate, cyclohexyl acetate, ethyl propionate, methyl butyrate, ethyl valerate, methyl chloroacetate, ethyl dichloroacetate, methyl methacrylate, ethyl crotonate, ethyl cyclohexanecarbonate, methyl benzoate, ethyl benzoate, propyl benzoate, butyl benzoate, octyl benzoate, cyclohexyl benzoate, phenyl benzoate, benzyl benzoate, methy toluylate, ethyl toluylate, amyl toluylate, ethyl ethylbenzoate, methyl anisate, ethyl anisate, ethoxy ethylbenzate, .gamma.-butyrolactone, .delta.-valerolactone, cumarin, phthalide, ethyl carbonate and the like, PA1 acid halides having from 2 to 15 carbon atoms, such as acetyl chloride, benzoyl chloride, toluic acid chloride, anisic acid chloride and the like, PA1 ethers having from 2 to 20 carbon atoms, such as methyl ether, ethyl ether, isopropyl ether, butyl ether, amyl ether, tetrahydrofuran, anisole, diphenyl ether and the like, PA1 acid anhydrides, such as acetic anhydride, phthalic anhydride, benzoic anhydride and the like, PA1 alkoxysilanes, such as ethyl silicate, diphenyldimethoxysilane and the like, PA1 acid amides, such as acetic N,N-dimethylamide, benzoic acid N,N-diethylamide, toluic acid N,N-dimethylamide and the like, PA1 amines, such as trimethylamine, triethylamine, tributylamine, tribenzylamine, tetramethylethylenediamine and the like, PA1 nitriles, such as acetonitrile, benzonitrile, trinitrile and the like, and PA1 pyridines, such as pyridine, methylpyridine, ethylpyridine, dimethylpyridine and the like. PA1 0&lt;m.ltoreq.3, 0.ltoreq.n&lt;3, 0.ltoreq.q&lt;3, and m+n+q=3. PA1 trialkylaluminum such as triethylaluminum and tributylaluminum; PA1 trialkenylaluminum such as triisopropenylaluminum; PA1 dialkylaluminum alkoxide such as diethylaluminum ethoxide and dibutylaluminum butoxide; and PA1 ethylaluminum sesquiethoxide, butylaluminum sesquibutoxide and partially alkoxylated alkylaluminum having an average composition, which is represented for example by the formula R.sup.1.sub.2.5 Al(OR.sup.2).sub.0.5. PA1 dialkylaluminum halide such as diethylaluminum chloride, dibutylaluminum chloride and diethylaluminum bromide; PA1 alkylaluminum sesquihalide such as ethylaluminum sesquichloride, butylaluminum sesquichloride and ethylaluminum sesquibromide; and PA1 partially halogenated alkylaluminum such as ethylaluminum dichloride, propylaluminum dichloride and butylaluminum dibromide. PA1 dialkylaluminum hydride such as diethylaluminum hydride and dibutylaluminum hydride; and PA1 partially hydrogenated alkylaluminum such as ethylaluminum dihydride and propylaluminum dihydride. PA1 partially alkoxylated and halogenated alkylaluminum such as ethylaluminum ethoxychloride, butylaluminum butoxychloride and ethylaluminum ethoxybromide. PA1 (C.sub.2 H.sub.5).sub.2 AlOAl(C.sub.2 H.sub.5).sub.2, PA1 (C.sub.4 H.sub.9).sub.2 AlOAl(C.sub.4 H.sub.9).sub.2 and ##STR24## PA1 the alkyl group includes methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, t-butyl group, pentyl group, hexyl group, octyl group, decyl group and dodecyl group; PA1 the cycloalkyl group includes cyclopentyl group and cyclohexyl group; PA1 the aryl group includes phenyl group and tolyl group; and PA1 the aralkyl group includes benzyl group and neophyl group. PA1 aryloxy group includes phenoxy group; PA1 sulfonic acid containing group (--SO.sub.3 R.sup.a) includes methanesulfonate group, p-toluenesulfonate group, trifluoromethanesulfonate group and p-chlorobenzenesulfonate group; and PA1 the halogen atom includes fluorine, chlorine, bromine and iodine. PA1 (1) a process comprising adding an organoaluminum compound such as trialkylaluminum to an aromatic hydrocarbon suspension of a compound containing adsorbed water, or a salt containing water of crystallization such as magnesium chloride hydrate, copper sulfate hydrate, aluminum sulfate hydrate, nickel sulfate hydrate or cerous chloride hydrate, to react them with each other, and obtaining aluminoxane in the form of a solution of said aluminoxane in aromatic hydrocarbon medium; PA1 (2) a process comprising adding water, ice or steam directly to an organoaluminum compound such as trialkylaluminum in a medium such as benzene, toluene, ethyl ether or tetrahydrofuran, and obtaining aluminoxane in the form of a solution of said aluminoxane in aromatic hydrocarbon medium; and PA1 (3) a process comprising reacting an organotinoxide such as dimethyltinoxide and dibutyltinoxide with an organoaluminum compound such as trialkylaluminum in a solvent such as decane, benzene or toluene. PA1 trialkylaluminums such as trimethylaluminum, triethylaluminum, tripropylaluminum, triisopropylaluminum, tri-n-butylaluminum, triisobutylaluminum, tri-sec-butylaluminum, tri-tert-butylaluminum, tripentylaluminum, trihexylaluminum, trioctylaluminum and tridecylaluminum; PA1 tricycloalkylaluminums such as tricyclohexylaluminum and tricyclooctylaluminum; PA1 dialkylaluminum halides such as dimethylaluminum chloride, diethylaluminum chloride, diethylaluminum bromide and diisobutylaluminum chloride; PA1 dialkylaluminum hydrides such as diethylaluminum hydride and diisobutylaluminum hydride; PA1 dialkylaluminum alkoxides such as dimethylaluminum methoxide and diethylaluminum ethoxide; and PA1 dialkylaluminum aryloxides such as diethylaluminum phenoxide. PA1 (i--C.sub.4 H.sub.9).sub.x Al.sub.y (C.sub.5 H.sub.10).sub.z PA1 alkenylaluminum such as isoprenylaluminum, etc; PA1 dialkylaluminum halides such as dimethylaluminum chloride, diethylaluminum chloride, diisopropylaluminum chloride, diisobutylaluminum chloride, dimethylaluminum bromide, etc; PA1 alkylaluminum sesquihalides such as methylaluminum sesquichloride, ethylaluminum sesquichloride, isopropylaluminum sesquichloride, butylaluminum sesquichloride, ethylaluminum sesquibromide, etc; PA1 alkylaluminum dihalides such as methylaluminum dichloride, ethylaluminum dichloride, isopropylaluminum dichloride, ethylaluminum dibromide, etc, and PA1 alkylaluminum hydride such as diethylaluminum hydride and diisobutylaluminum hydride. PA1 Compounds of the formula R.sup.5.sub.n Al(OR.sup.6).sub.3-n such as dimethylaluminum methoxide, diethylaluminum ethoxide, diisobutylaluminum methoxide, etc; PA1 (ii) Compounds of the formula R.sup.5.sub.n Al(OSiR.sup.7.sub.3).sub.3-n such as Et.sub.2 Al(OSiMe.sub.3), (iso-Bu).sub.2 Al(OSiMe.sub.3), (iso-Bu).sub.2 Al(OSiEt.sub.3), etc; PA1 (iii) Compounds of the formula R.sup.5.sub.n Al(OAlR.sup.8.sub.2).sub.3-n such as Et.sub.2 AlOAlEt.sub.2, (iso-Bu).sub.2 AlOAl(iso-Bu).sub.2, etc; PA1 (iv) Compounds of the formula R.sup.5.sub.n Al(NR.sup.9.sub.2).sub.3-n such as Me.sub.2 AlNEt.sub.2, Et.sub.2 AlNHMe, Me.sub.2 AlNHEt, Et.sub.2 AlN(SiMe.sub.3).sub.2, (iso-Bu).sub.2 AlN(SiMe.sub.3).sub.2, etc; PA1 (v) Compounds of the formula R.sup.5.sub.n Al(SiR.sup.10.sub.3).sub.3-n such as (iso-Bu).sub.2 AlSiMe.sub.3, etc; and PA1 (vi) Compounds of the formula ##STR28## such as ##STR29## PA1 alicyclic hydrocarbons such as cyclohexane, methylcyclopentane and methylcyclohexane, and halogen derivatives thereof; PA1 aromatic hydrocarbons such as benzene, toluene and xylene, and halogen derivatives such as chlorobenzene. In the above-mentioned copolymerization reaction, the .alpha.-olefin or cycloolefin itself may be used as the hydrocarbon solvent. These solvents may be used as the mixture thereof. PA1 (i) .alpha.-olefin/diene copolymers, PA1 (ii) .alpha.-olefin/cycloolefin/diene copolymers, and PA1 (iii) butadiene copolymers. PA1 (i) catalysts formed from soluble vanadium compounds and organoaluminum compounds, or PA1 (ii) catalysts formed from metallocene compounds of transition metals selected from the Group IV B of the periodic table or lanthanides series, organoaluminum oxy compounds and, if necessary, organoaluminum compounds. PA1 The test was conducted in accordance with ASTM D790. PA1 Shape of the test specimen: 5.times.1/2.times.1/8 t inch PA1 Span: 51 mm PA1 The measurement was made in accordance with ASTM D256. PA1 Shape of the test specimen: 5/2.times.1/8.times.1/2 t inch (notched) PA1 Test temperature: 23.degree. C.
Further, it has been found also that particularly in the case of (2) mentioned above, when a cycloolefin elastomer is used as the hydrocarbon elastomer having the polymerizable carbon-carbon double bond, the resulting cycloolefin random copolymer composition becomes excellent in impact resistance, while maintaining excellent transparency inherent in cycloolefin random copolymers.